The motor has two voltages of interest - firstly the steady state voltage applied to the winding for the rated current and - secondly the insulation breakdown voltage at the highest temperature the motor can reach.
The electronics switch the appled power on and off to regulate the current. The current increases slowly due to the inductance of the motor coil. Thus there is no direct relationship between the voltage of the driving electronics and the rated motor other than the need to stay within the safe working limits of the componets used. The electronics use various methods to determine the point at which the drive pulse needs to stop to stay with in the safe current rating of the motor winding.
There is no harm, apart from loss of power, in setting the current lower than the maximum for the motor.
On the assumption that this is a stepper driver a higher voltage gives better high speed potential.